Process and apparatus for deasphalting and pitch conversion

ABSTRACT

Solvent deasphalting (SDA) is used to extract deasphalted oil from heavier hydrocarbons in series. The pitch stream from solvent deasphalting is calcined to recover volatile hydrocarbon vapor products and calcined solids. The hydrocarbon vapors can be fractionated to recover valuable transportation range fuel products. The pitch stream can be first fed to the fractionation column before calcination.

FIELD

The field relates to a process and apparatus for separating heavy hydrocarbon feed by solvent deasphalting into a lighter hydrocarbon stream.

BACKGROUND

As the reserves of conventional crude oils decline, heavy oils must be upgraded to meet market demands. Crude oil is typically first processed in an atmospheric crude distillation tower to provide fuel products including naphtha, kerosene and diesel. The atmospheric crude distillation resid bottoms stream is typically taken to a vacuum distillation tower to obtain vacuum gas oil (VGO) that can be feedstock for an FCC unit or a hydrocracking unit and vacuum residue (VR).

Solvent deasphalting (SDA) generally refers to refinery processes that upgrade hydrocarbon fractions using extraction in the presence of a solvent. The hydrocarbon fractions are often obtained from the distillation of crude oil, and include hydrocarbon residues or gas oils from atmospheric or vacuum column distillation. SDA permits practical recovery of higher quality oil, at relatively low temperatures, without cracking or degradation of heavy hydrocarbons. SDA separates hydrocarbons according to their solubility in a liquid solvent, as opposed to volatility in distillation. Lower molecular weight and most aliphatic components are preferentially extracted. The least soluble materials are high molecular weight and mostly aromatic and polar components. This makes the deasphalted oil (DAO) extract light and aliphatic, and the asphaltic raffinate also known as pitch, heavy and aromatic. Suitable solvents for SDA include propane and higher molecular weight paraffins, such as butane and pentane, for example. The pitch stream generally contains metal compounds as well as high molecular weight hydrocarbons.

SDA typically recovers no more than about 40 wt % product. Hence, further recovery is very desirable in SDA to make it worthwhile. Once the SDA pitch stream is stripped to remove residual solvent, finding a cost-effective outlet for the stripped pitch is challenging for the refiner. Making asphalt using stripped pitch is not always a feasible option. Burning stripped pitch along with requisite gas treating is a very expensive solution. Pelletizing of stripped pitch is also an expensive solution and pelletized pitch is likely to re-mass during transportation.

There is an ongoing need to improve conversion and disposal of pitch from a deasphalting processes and apparatus to increase recovery.

SUMMARY

We have discovered a process and apparatus that improves recovery of valuable hydrocarbon from solvent deasphalting. The SDA pitch stream is delivered to a calciner that vaporizes smaller hydrocarbons and thermally cracks larger hydrocarbons producing a vapor product stream while leaving a calcined solids stream. The vapor product stream may be separated in the same separator to which the pitch stream is fed to heat the latter. The separator may recover at least one hydrocarbon product stream.

Definitions

As used herein, the term “communication” means that material flow is operatively permitted between enumerated components.

As used herein, the term “downstream communication” means that at least a portion of material flowing to the component in downstream communication may operatively flow from the component with which it communicates.

As used herein, the term “upstream communication” means that at least a portion of the material flowing from the component in upstream communication may operatively flow to the component with which it communicates.

The term “direct communication” means that flow from the upstream component enters the downstream component without passing through a fractionation or conversion unit to undergo a compositional change due to physical fractionation or chemical conversion.

The term “indirect communication” means that flow from the upstream component enters the downstream component after passing through a fractionation and/or conversion unit to undergo a compositional change due to physical fractionation or chemical conversion.

As used herein, the term “a component-rich stream” means that the rich stream coming out of a separator vessel has a greater concentration of the component than the feed to the separator vessel.

As used herein, the term “a component-lean stream” means that the lean stream coming out of a separator vessel has a smaller concentration of the component than the feed to the separator vessel.

The term “column” means a distillation column or columns for separating one or more components of different volatilities. Unless otherwise indicated, each column includes a condenser on an overhead of the column to condense and reflux a portion of an overhead stream back to the top of the column and a reboiler at a bottom of the column to vaporize and send a portion of a bottoms stream back to the bottom of the column. Feeds to the columns may be preheated. The top pressure is the pressure of the overhead vapor at the vapor outlet of the column. The bottom temperature is the liquid bottom outlet temperature. Overhead lines and bottoms lines refer to the net lines from the column downstream of any reflux or reboil to the column. Stripper columns may omit a reboiler at a bottom of the column and instead provide heating requirements and separation impetus from a fluidized inert media such as steam. Stripping columns typically feed a top tray and take main product from the bottom.

As used herein, the term “True Boiling Point” (TBP) means a test method for determining the boiling point of a material which corresponds to ASTM D-2892 for the production of a liquefied gas, distillate fractions, and residuum of standardized quality on which analytical data can be obtained, and the determination of yields of the above fractions by both mass and volume from which a graph of temperature versus mass % distilled is produced using fifteen theoretical plates in a column with a 5:1 reflux ratio.

As used herein, the term “initial boiling point” (IBP) means the temperature at which the sample begins to boil using ASTM D-7169 or TBP as the case may be.

As used herein, the term “T5”, “T70” or “T95” means the temperature at which 5 mass percent, 70 mass percent or 95 mass percent, as the case may be, respectively, of the sample boils using ASTM D-7169 or TBP as the case may be.

As used herein, the term “separator” means a vessel which has an inlet and at least an overhead vapor outlet and a bottoms liquid outlet and may also have an aqueous stream outlet from a boot. A flash drum is a type of separator which may be in downstream communication with a separator which latter may be operated at higher pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a process and apparatus.

FIG. 2 is a schematic view of an alternative embodiment of the process and apparatus of FIG. 1.

DETAILED DESCRIPTION

Embodiments of the invention relate to the use of SDA to prepare a heavy hydrocarbon feedstock for upgrading. According to one embodiment, for example, the heavy hydrocarbon feedstock comprises residual oils such as an atmospheric residuum having an IBP of at least about 232° C. (450° F.), a T5 of about 288° C. (550° F.) and about 392° C. (700° F.), typically no more than about 343° C. (650° F.), and a T95 between about 510° C. (950° F.) and about 700° C. (1292° F.) obtained from the bottoms of an atmospheric crude distillation column. Another heavy hydrocarbon feedstock is vacuum residuum having an IBP of at least 500° C. (932° F.). Tars, bitumen, coal oils, and shale oils may be additional heavy hydrocarbon feed stocks. Other asphaltene-containing materials such as whole or topped petroleum crude oils including heavy crude oils may also be used as components processed by SDA. In addition to asphaltenes, these further possible components of the heavy hydrocarbon feedstock, as well as others, generally also contain significant metallic contaminants, e.g., nickel, iron and vanadium, a high content of organic sulfur and nitrogen compounds, and a high Conradson carbon residue. The metals content of such components, for example, may be 100 ppm to 1,000 ppm by weight, the total sulfur content may range from 1% to 7% by weight, and the API gravity may range from about −5° to about 35°. The Conradson carbon residue of such components is generally at least about 5%, and is often from about 10% to about 30%, by weight.

As shown in FIG. 1, a process and apparatus 10 for extracting lighter hydrocarbons from heavier hydrocarbons is exemplified by a solvent deasphalting unit 12. A heavy hydrocarbon feed stream in a heavy feed line 20 may be transported to the solvent deasphalting unit 12. In the SDA process, the heavy hydrocarbon feed stream in the heavy feed line 20 is pumped and admixed with a mixing solvent stream in a mixing solvent line 22 before entering into an extraction column 24. An additional solvent stream, for example, in an additional solvent line 28, may be added to a lower end of the extraction column 24 through an additional solvent inlet 28 i. An extractor inlet line 26 in downstream communication with the heavy feed line 20 and the mixing solvent line 22 may deliver mixed feed to the extraction column 24 through the extractor inlet line to a mixed inlet 26 i. A solvent, typically propane or butanes, or mixtures thereof solubilizes the lighter aliphatic hydrocarbon material in the heavy hydrocarbon feed. Trays or packing may be utilized in the extraction column 24 above each solvent inlet 26 i, 28 i to dislodge asphaltic compounds from solubilized deasphalted oil rising in the column. A DAO stream is extracted from the heavy hydrocarbon feed stream and exits the extraction column 24 in a DAO line 30 extending from an overhead of the extraction column 24. The heavier aromatic and polar components of the feed are insoluble in the solvent and precipitate out as an asphaltene or pitch stream in a pitch line 32 extending from a bottom of the extraction column 24. The extraction column 24 may typically operate at about 70° C. (158° F.) to about 204° C. (400° F.) and about 3.8 MPa (550 psia) to about 5.5 MPa (800 psia).

The DAO stream in the DAO line 30 has a greater concentration of aliphatic compounds than in the heavy hydrocarbon feed stream in the heavy feed line 20. The DAO stream is heated to supercritical temperature for the solvent by indirect heat exchange with a separated solvent stream in a separated solvent line 36 in heat exchanger and in a subsequent heater or additional heat exchanger and is fed to the DAO separator column 40 through a DAO inlet 30 i . The super critically heated solvent separates from the DAO in a DAO separator column 40 which is in downstream communication with the DAO line 30 from the overhead of the extraction column 24. The DAO separator column 40 may be in downstream communication with the DAO line 30 of the extraction column 24. A separated solvent stream exits the DAO separator column 40 in the separator solvent line 36 extending from an overhead of the DAO separator column 40. Packing or trays in the DAO separator column above the DAO inlet 30 i may facilitate separation. A separated DAO stream exits in a separated DAO line 42 extending from a bottom of the DAO separator column 40. The solvent recycle stream is condensed by indirect heat exchange in a heat exchanger with the DAO stream in the DAO line 30 and a condenser. The DAO separator column 40 will typically operate at about 177° C. (350° F.) to about 287° C. (550° F.) and about 3.8 MPa (550 psia) to about 5.5 MPa (800 psia).

The pitch stream in the pitch line 32 contains a greater concentration of aromatic compounds than in the heavy feed stream in the heavy feed line 20. The pitch stream in the pitch line 32 is heated in a heater or by heat exchange and fed to a pitch stripper column 50 through a pitch inlet 32 i above an inlet for an inert gas line 52 and in downstream communication with said pitch line 32 to yield a solvent recovery stream in a solvent recovery line 54 extending from an overhead of the pitch stripper column 50 and a solvent-lean, stripped pitch stream in a stripped pitch line 56 extending from a bottoms of the pitch stripper column 50. Inert gas such as steam from line 52 distributed below the pitch inlet 32 i may be used as stripping fluid in the pitch stripper column 50. The pitch stripper column 50 will typically operate at about 204° C. (400° F.) to about 299° C. (570° F.) and about 344 kPa (50 psia) to about 1,034 kPa (150 psia).

A solvent-lean DAO steam exits the DAO separator column 40 in the separated DAO line 42 and enters a DAO stripper column 60 through a DAO stripper inlet 42 i in downstream communication with the separated DAO line 42. The DAO stripper column 60 further separates a stripper solvent stream in a stripper solvent line 64 extending from an overhead of said DAO stripper column from a deasphalted stream in a DAO product line 66 by stripping solvent from DAO at low pressure with an inert gas from line 62 with an inlet below the DAO stripper inlet 42 i. Steam in line 62 may be used as stripping fluid in the DAO stripper column 60. The DAO stripper column 60 will typically operate at about 149° C. (300° F.) to about 260° C. (500° F.) and about 344 kPa (50 psia) to about 1,034 kPa (150 psia). The additional solvent recovery stream leaves in the stripper solvent line 64 and joins the recovery solvent in the solvent recovery line 54 before being condensed by a cooler and received in solvent reservoir 68 which may comprise a boot for removing water. Recovered solvent is pumped from the reservoir 68 as necessary through solvent recycle line 70 to supplement the separated solvent in the separated solvent line 36 to facilitate extraction in the extraction column 24. Make-up solvent may be added at make-up line 72. Essentially solvent-free DAO is provided in line 66 comprising about 30 to about 50 wt % of the heavy feed in the heavy feed line 20.

The stripped pitch stream in the stripped pitch line 56 may be calcined in a calciner 80 to produce more hydrocarbon products. In the calciner 80, smaller hydrocarbons are vaporized and larger hydrocarbons are thermally cracked to produce a volatile, vapor product stream in a vapor product line 82 and leaving a calcined solids stream in a calcined solids line 84. A portion of calcined solids may be recycled to the inlet to the calciner 80 in a recycle line 86.

The calciner 80 can comprise an elongated, horizontally-oriented vessel that has a greater width than its height. The calciner 80 comprises an inlet end 81 which receives the pitch stream. The calciner 80 may be in downstream communication with the pitch line 32 and the stripped pitch line 56. The calciner 80 may have rotating equipment such as a rotating drum or baffles or paddles that mechanically move the pitch stream from the inlet end 81 generally, horizontally to an outlet end 83 under heating. The calcined solids line 84 may extend from at or near the outlet end 83. The vapor product stream may exit at or near a top 85 of the calciner in the vapor product line 82 that may extend from the top of the calciner 80. The calciner 80 may have a general cylindrical configuration and may be tapered or inclined from the inlet end 81 toward an outlet end 83 to allow gravity to assist movement of the stripped pitch stream form the inlet end to the outlet end.

The calciner 80 may comprise a rotary calciner, fired calciner, a fired rotary calciner or other substantially similar equipment. A fired calciner is preferably indirectly fired. A jacket 87 around the calciner 80 may receive a hydrocarbon stream in a fuel line 88 that is combusted to indirectly heat the calciner 80. The atmosphere in the calciner 80 is inert, which is preferably an oxygen-free nitrogen atmosphere, such as under nitrogen, but it may be any other inert non-oxidizing atmosphere or under vacuum. Calcining may occur at a temperature of about 450° C. (842° F.) to about 649° C. (1200° F.), preferably 500° C. (932° F.) to about 600° C. (1112° F.), and a pressure of about 4 kPa (0.6 psia) to about 344 kPa (50 psia), which temperature may be maintained for a sufficient residence time to produce the calcined solids in the calcined solids line 84 extending from or communicating with the outlet end 83 and the hot volatile, vapor product stream in the vapor product line 82. The calcined solids has the composition of petroleum coke and may be disposed of, used as fuel, further processed for recovery of metals or used as fuel in cement manufacture or as material for , carbon electrode, carbon black or metallurgical coke manufacturing.

The volatile, hydrocarbon product stream in the vapor product line 82 may be fed to a separator 140 to separate at least one hydrocarbon product stream. The separator 140 may be in downstream communication with the calciner 80. The separator 140 may be a fractionation column 140 that fractionates the vapor product stream to provide a plurality of product streams comprising an off-gas stream in off-gas line 142, a naphtha stream in net naphtha line 144, a diesel stream in a diesel line 146 and a gas oil stream in a gas oil line 148. A portion of the gas oil stream in gas oil line 148 may be cooled and pumped back around to the column 140 and sprayed over the rising vapors to wash entrained heavier hydrocarbons into the liquid stream in the bottom of the column. An inert gas such as steam from inert gas line 91 may be used to provide heat and stripping gas to the fractionation column 140. An overhead stream may be taken in an overhead line from the fractionation column 140, be condensed and separated in a receiver to provide the off-gas stream in the off-gas line 142 and the net naphtha stream in the net naphtha line 144 as well as reflux back to the column.

In an aspect, the stripped pitch stream in the stripped pitch line 56 may be fed to the separator 140 before it is fed to the calciner 80. The stripped pitch stream may cool the bottom of the separator 140 particularly when the separator is a fractionation column to prevent hydrocarbons entering the bottom from coking under high temperatures. In the separator 140, the stripped pitch stream will be heated by absorbing heat from the hot materials in the column, to preheat the stripped pitch stream. The preheated, stripped pitch stream may exit the bottom of the separator 140 in a bottoms line 150 and feed the calciner 80 at the inlet end 81. The calciner 80 may be in downstream communication with the bottoms line 150 of the separator 140. When the separator is a fractionation column, it may be operated at a top pressure of about 7 kPa (g) (1 psig) to about 345 kPa (g) (50 psig) and a bottom temperature of about 260° C. (500° F.) to about 399° C. (750° F.).

FIG. 2 shows an alternative embodiment of the process and apparatus 10′ of FIG. 1 that has a second stage 14 of solvent deasphalting. Elements in FIG. 2 with the same configuration as in FIG. 1 will have the same reference numeral as in FIG. 1. Elements in FIG. 2 which have a different configuration as the corresponding element in FIG. 1 will have the same reference numeral but designated with a prime symbol (′). Elements mentioned in FIG. 2 in the first stage 12′ of solvent deasphalting which have the same configuration as the corresponding element in FIG. 1 will have the same reference numeral but prefaced hereinafter as a first of its kind to distinguish it from the second such element of its kind in the second stage 14 of solvent deasphalting. The configuration and operation of the embodiment of FIG. 2 is similar to FIG. 1 with the following noted exceptions.

The solvent-lean, first stripped pitch stream in the stripped pitch line 56′ comprising the asphaltenes in the first pitch stream in the first pitch line 32 may be transported from the first stage 12′ of solvent deasphalting to the second stage 14 of solvent deasphalting. In the SDA process and apparatus 10′, the solvent-lean, first stripped pitch stream in the first stripped pitch line 56′ is pumped and admixed with a second mixing solvent stream in a second mixing solvent line 82 before entering into a second extraction column 84. An additional second solvent stream, for example, in an additional second solvent line 88, may be added to a lower end of the second extraction column 84 through an additional solvent inlet 88 i. A second extraction inlet line 86 in downstream communication with the first stripped pitch line 56′ and the first pitch line 32 and the second mixing solvent line 82 may deliver a mixed feed stream to the second extraction column 84 together to a second mixed inlet 86 i. A second solvent, typically butane or pentane, or mixtures thereof, that is heavier than the first solvent, solubilizes the aliphatic and lighter hydrocarbon material in the first pitch stream to provide a second pitch stream in a second pitch line 92 that is heavier than the first pitch stream in the first pitch line 32. Trays or packing may be utilized in the second extraction column 84 above each solvent inlet 86 i, 88 i to dislodge asphaltic materials from solubilized deasphalted oil rising in the column. A second DAO stream is extracted from the first pitch stream and exits the second extraction column 84 in a second DAO line 90 extending from an overhead of the second extraction column 84. The heavier and aromatic portions of the pitch stream are insoluble in the heavier solvent and precipitate out as a second asphaltene or pitch stream in a second pitch line 92 extending from a bottom of the second extraction column 84. The second extraction column 84 may typically operate at about 93° C. (200° F.) to about 204° C. (400° F.) and about 3.8 MPa (550 psia) to about 5.5 MPa (800 psia).

The second DAO stream in the second DAO line 90 has a greater concentration of aliphatic compounds than in the first pitch stream in the first stripped pitch line 56′. The second DAO stream is heated to supercritical temperature for the second solvent by indirect heat exchange with a second separated solvent stream in a second separated solvent line 96 in a heat exchanger and in a subsequent heater or additional heat exchanger and is fed to the second DAO separator column 100 through a second DAO inlet 90 i. The super critically heated solvent separates from the DAO in the second DAO separator column 100 which is in downstream communication with the second DAO line 90 of the second extraction column 84. The second DAO separator column 100 may be in downstream communication with the second DAO line 90 of the second extraction column 84. A second separated solvent stream exits the second DAO separator column 100 in the second separator solvent line 96 extending from an overhead of the second DAO separator column 100. Packing or trays in the second DAO separator column above the second DAO inlet 90 i may facilitate separation. A second separated DAO stream exits in a second separated DAO line 102 extending from a bottom of the second DAO separator column 100. The second separated solvent stream in the second separator solvent line 96 is condensed by indirect heat exchange in the heat exchanger with the second DAO stream in the second DAO line 90 and a condenser. The DAO separator column 100 will typically operate at about 177° C. (350° F.) to about 287° C. (550° F.) and about 3.8 MPa (550 psia) to about 5.5 MPa (800 psia).

A second solvent-lean DAO steam exits the second DAO separator column 100 in a second separated DAO line 102 and enters a second DAO stripper column 120 through a second DAO stripper inlet 102 i in downstream communication with the second separated DAO line 102. The second DAO stripper column 120 further separates a second stripper solvent stream in a second stripper solvent line 124 extending from an overhead of the DAO stripper column from a second deasphalted stream in a second deasphalted line 126 extending from a bottom of the second DAO stripper column by stripping solvent from the DAO components at low pressure with an inert gas from line 122 with an inlet below the DAO stripper inlet 102 i. Steam in line 122 may be used as stripping fluid in the second DAO stripper column 120. The second DAO stripper column 120 will typically operate at about 149° C. (300° F.) to about 260° C. (500° F.) and about 344 kPa (50 psia) to about 1,034 kPa (150 psia). The second solvent stream leaves in the second stripper solvent line 124 and joins the second recovery solvent stream in a second solvent recovery line 114 before being condensed by a cooler and received in solvent reservoir 128 which may comprise a boot for removing water. Recovered solvent is pumped from the reservoir 128 as necessary through solvent recycle line 130 to supplement the second separated solvent stream in the second separated solvent line 96 to facilitate extraction in the second extraction column 84. Make-up second solvent may be added by a second make up line 132. Essentially, a second solvent-free DAO stream is provided in the second deasphalted line 126 comprising about 10 to about 30 wt% of the heavy feed in the heavy feed line 20 giving an aggregate DAO recovery of 40 to about 80 wt% of the heavy feed in the heavy feed line.

The second pitch stream in the second pitch line 92 contains a greater concentration of aromatic compounds than in the first stripped pitch stream in the first stripped pitch line 56′, or than the first pitch stream in the first pitch line 32 excluding the solvent in the second pitch stream. However, the second pitch stream comprises the second solvent that must be removed. The second pitch stream in the second pitch line 92 is heated in a heater or by heat exchange and fed to a second pitch stripper 110 through a first pitch inlet 92 i above an inlet for an inert gas line 128 and in downstream communication with said second pitch line 92 to yield a second solvent recovery stream in a second solvent recovery line 114 extending from an overhead of the second pitch stripper column 110 and a second solvent-lean, stripped pitch stream in a second stripped pitch line 116 extending from a bottoms of the second pitch stripper column 110. Inert gas such as steam from line 112 distributed below the second pitch inlet 92 i may be used as stripping fluid in the second pitch stripper column 118. The second pitch stripper column 110 will typically operate at about 204° C. (400° F.) to about 299° C. (570° F.) and about 344 kPa (50 psia) to about 1,034 kPa (150 psia).

Stripping the second pitch stream in the second pitch stripper column 110 as conducted in the first stage of solvent deasphalting 12 may produce a second stripped pitch stream that could set up and present difficulty in consistent removal from a second pitch stripper. Hence, a portion of a product stream from the fractionation column 140 is mixed with the second stripped pitch stream in the bottom of the second pitch stripper column 110 to assist in transporting the second pitch stream to the calciner 80. In an aspect, the product stream that cuts the second pitch stream may be gas oil taken from the gas oil line 148′ and transported to the second pitch stripper column 110 in a cutter line 132. The product stream may enter the second pitch stripper column 110 at an inlet at or below the inlet for the stripping inert gas from line 112. The stripped pitch stream cut with the product stream from cutter line 132 may be transported to the calciner 80 in the second stripped pitch line 116. In an aspect, the stripped pitch stream cut with the product stream in the second stripped pitch line 116 may be transported to the fractionation column 140 in the second stripped pitch line 116 where much of the product stream will flash off because the fractionation column 140 is operated hotter than the second pitch stripper 110. The fractionation column 140 will be operated to allow the second pitch stream to enter the bottoms line 150and be transported from the fractionation column 140 in the bottoms line 150 to the calciner 80.

With these noted exceptions, the embodiment of FIG. 2 operates as the embodiment in FIG. 1.

EXAMPLE

A stream of stripped, solvent deasphalted pitch at 70% lift was subjected to rotary calcination with indirect heating in a self-inerting environment at a pressure of 48 kPa (absolute) and in a temperature range shown in the Table below. The calcined solids were recovered from calcination and subjected to crucible heating at 950° C. to determine the residue of volatile hydrocarbons not recovered according to ASTM D3175. The fraction of volatile hydrocarbons of the calcined solid stream not recovered from the stripped pitch feed is indicated in the Table.

Temperature Volatile Run No. Operation Mode Range, ° C. Hydrocarbons, wt % 1 Once-through 403-503 12.2 2 Once-through 420-529 11.7 3 Dried Solids Recycle 425-506 8.0 Calcination resulted in minimal volatile hydrocarbons not recovered. Solids recycle provided further minimized presence of volatile hydrocarbons on calcined solids.

Specific Embodiments

While the following is described in conjunction with specific embodiments, it will be understood that this description is intended to illustrate and not limit the scope of the preceding description and the appended claims.

A first embodiment of the invention is a process for extracting lighter hydrocarbons from heavier hydrocarbons comprising deasphalting a heavy hydrocarbon feed stream with a solvent stream to extract a deasphalted oil stream containing a greater concentration of aliphatic compounds than in the feed stream and provide a pitch stream containing a greater concentration of aromatic compounds than in the feed stream; calcining the pitch stream to produce a vapor product stream and provide a calcined solid stream; and separating the vapor product stream to provide a product stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising feeding the pitch stream to a separator before calcining the pitch stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising feeding the vapor product stream to the separator. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the separator is a fractionation column and pitch stream absorbs heat from the fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising stripping the pitch stream to separate a solvent recovery stream from the pitch stream to provide a stripped pitch stream which is calcined. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the heavy hydrocarbon feed stream is a first pitch stream, the solvent stream is a second solvent stream, the deasphalted oil stream is a second deasphalted oil stream and the pitch stream is a second pitch stream and further comprising deasphalting a first heavy hydrocarbon stream with a first solvent stream to extract a first deasphalted oil stream containing a greater concentration of aliphatic compounds than in the first heavy hydrocarbon stream and provide the first pitch stream containing a greater concentration of aromatic compounds than in the first heavy hydrocarbon stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising stripping the pitch stream to separate a solvent recovery stream from the pitch stream to provide a stripped pitch stream, calcining the stripped pitch stream and mixing the product stream with the stripped pitch stream prior to calcining. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the calcining step is conducted in an elongated vessel in which the pitch stream is moved horizontally from an inlet end to an outlet end as it is heated. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising fractionating the vapor product stream to provide a plurality of product streams. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising separating a deasphalted oil stream into a separated solvent stream and a separated deasphalted oil stream and stripping the separated deasphalted oil stream to provide a stripper solvent stream and a deasphalted stream and recycling the solvent recovery stream, the separated solvent stream and the stripper solvent stream to the deasphalting step.

A second embodiment of the invention is an apparatus for solvent deasphalting comprising an extraction column having a heavy feed inlet and a solvent inlet, a deasphalted oil line extending from an overhead of the first extraction column and a pitch line extending from a bottom of the extraction column; a calciner in downstream communication with the pitch line; and a separator in downstream communication with the calciner. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph, wherein the calciner has an inlet end and an outlet end and a calcined solids line extending from the outlet end and a vapor product line extending from a top of the calciner. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein the separator is in downstream communication with the pitch line and the calciner is in downstream communication with the separator. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising a pitch stripper column comprising a pitch inlet above an inert gas inlet and in downstream communication with the pitch line, and a solvent recovery line extending from an overhead of the pitch stripper column and a stripped pitch line extending from a bottom of the pitch stripper column wherein the calciner is in downstream communication with the pitch stripper line. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising a second extraction column in communication with the pitch line, the second extraction column having a second heavy feed inlet and a second solvent inlet, a second deasphalted oil line extending from an overhead of the second extraction column and a second pitch line extending from a bottom of the second extraction column and the calciner is in downstream communication with the second pitch line. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising a deasphalted oil separator having a separator solvent line extending from an overhead of the deasphalted oil separator and a separator DAO line extending from a bottom of the deasphalted oil separator and a deasphalted oil stripper column having a deasphalted oil stripper inlet above an inert gas inlet and in downstream communication with the separator DAO line and the deasphalted oil stripper column having a stripper solvent line extending from an overhead of the deasphalted oil striper column and a DAO product stream extending from a bottom of the deasphalted oil stripper column.

A third embodiment of the invention is a process for extracting lighter hydrocarbons from heavier hydrocarbons comprising deasphalting a heavy hydrocarbon feed stream with a solvent to extract a deasphalted oil stream containing a greater concentration of aliphatic compounds than in the feed stream and provide a pitch stream containing a greater concentration of aromatic compounds than in the feed stream; passing the pitch stream to a fractionation column; and calcining the pitch stream from the fractionation column to vaporize light hydrocarbons and crack heavier hydrocarbons. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph further comprising fractionating a vapor product stream from the calciner in the fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph wherein the heavy hydrocarbon feed stream is a first pitch stream, the solvent stream is a second solvent stream, the deasphalted oil stream is a second deasphalted oil stream and the pitch stream is a second pitch stream and further comprising deasphalting a first heavy hydrocarbon stream with a first solvent stream to extract a first deasphalted oil stream containing a greater concentration of aliphatic compounds than in the first heavy hydrocarbon stream and provide the first pitch stream containing a greater concentration of aromatic compounds than in the first heavy hydrocarbon stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph wherein the calcining step is conducted in an elongated vessel in which the pitch stream is moved horizontally from an inlet end to an outlet end as it is heated.

Without further elaboration, it is believed that using the preceding description that one skilled in the art can utilize the present invention to its fullest extent and easily ascertain the essential characteristics of this invention, without departing from the spirit and scope thereof, to make various changes and modifications of the invention and to adapt it to various usages and conditions. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limiting the remainder of the disclosure in any way whatsoever, and that it is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

In the foregoing, all temperatures are set forth in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated. 

1. A process for extracting lighter hydrocarbons from heavier hydrocarbons comprising: deasphalting a heavy hydrocarbon feed stream with a solvent stream to extract a deasphalted oil stream containing a greater concentration of aliphatic compounds than in the feed stream and provide a pitch stream containing a greater concentration of aromatic compounds than in the feed stream; calcining the pitch stream to produce a vapor product stream and provide a calcined solid stream; and separating said vapor product stream to provide a product stream.
 2. The process of claim 1 further comprising feeding said pitch stream to a separator before calcining said pitch stream.
 3. The process of claim 2 further comprising feeding said vapor product stream to said separator.
 4. The process of claim 3 wherein said separator is a fractionation column and pitch stream absorbs heat from said fractionation column.
 5. The process of claim 2 further comprising stripping said pitch stream to separate a solvent recovery stream from said pitch stream to provide a stripped pitch stream which is calcined.
 6. The process of claim 1 wherein said heavy hydrocarbon feed stream is a first pitch stream, said solvent stream is a second solvent stream, said deasphalted oil stream is a second deasphalted oil stream and said pitch stream is a second pitch stream and further comprising: deasphalting a first heavy hydrocarbon stream with a first solvent stream to extract a first deasphalted oil stream containing a greater concentration of aliphatic compounds than in the first heavy hydrocarbon stream and provide said first pitch stream containing a greater concentration of aromatic compounds than in the first heavy hydrocarbon stream.
 7. The process of claim 6 further comprising stripping said pitch stream to separate a solvent recovery stream from said pitch stream to provide a stripped pitch stream, calcining said stripped pitch stream and mixing said product stream with said stripped pitch stream prior to calcining.
 8. The process of claim 1 wherein said calcining step is conducted in an elongated vessel in which the pitch stream is moved horizontally from an inlet end to an outlet end as it is heated.
 9. The process of claim 1 further comprising fractionating said vapor product stream to provide a plurality of product streams.
 10. The process of claim 5 further comprising separating a deasphalted oil stream into a separated solvent stream and a separated deasphalted oil stream and stripping said separated deasphalted oil stream to provide a stripper solvent stream and a deasphalted stream and recycling the solvent recovery stream, the separated solvent stream and the stripper solvent stream to the deasphalting step.
 11. An apparatus for solvent deasphalting comprising: an extraction column having a heavy feed inlet and a solvent inlet, a deasphalted oil line extending from an overhead of the first extraction column and a pitch line extending from a bottom of said extraction column; a calciner in downstream communication with said pitch line; and a separator in downstream communication with said calciner.
 12. The apparatus of claim 11, wherein said calciner has an inlet end and an outlet end and a calcined solids line extending from the outlet end and a vapor product line extending from a top of the calciner.
 13. The apparatus of claim 11 wherein said separator is in downstream communication with said pitch line and said calciner is in downstream communication with said separator.
 14. The apparatus of claim 11 further comprising a pitch stripper column comprising a pitch inlet above an inert gas inlet and in downstream communication with said pitch line, and a solvent recovery line extending from an overhead of said pitch stripper column and a stripped pitch line extending from a bottom of the pitch stripper column wherein said calciner is in downstream communication with said pitch stripper line.
 15. The apparatus of claim 11 further comprising a second extraction column in communication with said pitch line, said second extraction column having a second heavy feed inlet and a second solvent inlet, a second deasphalted oil line extending from an overhead of the second extraction column and a second pitch line extending from a bottom of said second extraction column and said calciner is in downstream communication with said second pitch line.
 16. The apparatus of claim 11 further comprising a deasphalted oil separator having a separator solvent line extending from an overhead of said deasphalted oil separator and a separator DAO line extending from a bottom of said deasphalted oil separator and a deasphalted oil stripper column having a deasphalted oil stripper inlet above an inert gas inlet and in downstream communication with the separator DAO line and said deasphalted oil stripper column having a stripper solvent line extending from an overhead of said deasphalted oil striper column and a DAO product stream extending from a bottom of the deasphalted oil stripper column.
 17. A process for extracting lighter hydrocarbons from heavier hydrocarbons comprising: deasphalting a heavy hydrocarbon feed stream with a solvent to extract a deasphalted oil stream containing a greater concentration of aliphatic compounds than in the feed stream and provide a pitch stream containing a greater concentration of aromatic compounds than in the feed stream; passing said pitch stream to a fractionation column; and calcining the pitch stream from the fractionation column to vaporize light hydrocarbons and crack heavier hydrocarbons.
 18. The process of claim 17 further comprising fractionating a vapor product stream from said calciner in said fractionation column.
 19. The process of claim 17 wherein said heavy hydrocarbon feed stream is a first pitch stream, said solvent stream is a second solvent stream, said deasphalted oil stream is a second deasphalted oil stream and said pitch stream is a second pitch stream and further comprising: deasphalting a first heavy hydrocarbon stream with a first solvent stream to extract a first deasphalted oil stream containing a greater concentration of aliphatic compounds than in the first heavy hydrocarbon stream and provide said first pitch stream containing a greater concentration of aromatic compounds than in the first heavy hydrocarbon stream.
 20. The process of claim 17 wherein said calcining step is conducted in an elongated vessel in which the pitch stream is moved horizontally from an inlet end to an outlet end as it is heated. 